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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society for railway
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Journal DOI :
Korean Society for Railway
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Volume & Issues
Volume 16, Issue 6 - Dec 2013
Volume 16, Issue 5 - Oct 2013
Volume 16, Issue 4 - Aug 2013
Volume 16, Issue 3 - Jun 2013
Volume 16, Issue 2 - Apr 2013
Volume 16, Issue 1 - Feb 2013
Selecting the target year
Dynamic Property Evaluation of Four-Harness Satin Woven Glass/epoxy Composites for a Composite Bogie Frame
Kim, Il Kyeom ; Kim, Jung Seok ; Seo, Sung Il ; Lee, Woo Geun ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 1~6
DOI : 10.7782/JKSR.2013.16.1.001
In this study, the natural frequency and damping ratio of a four-harness satin woven glass/epoxy composite material are evaluated by means of modal tests and a finite element analysis. To achieve this goal, glass/epoxy beam specimens with different lengths and thicknesses were manufactured via autoclave curing. In the test, the maximum damping ratio was found to occur at the lowest test frequency. As the test frequency increased, the damping ratio decreased exponentially to a critical value. After that value, the damping ratio increased gradually to the maximum test frequency.
Analysis of the Vibration Characteristics of a High-Speed Train using a Scale Model
Han, Jae Hyun ; Kim, Tae Min ; Kim, Jeung Tae ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 7~13
DOI : 10.7782/JKSR.2013.16.1.007
A scaled version of a roller rig is developed to demonstrate the dynamic characteristics of a railway vehicle for academic purposes. This rig is designed based on Jaschinski's similarity law. It is scaled to 1/10 of actual size and allows 9-DOF motion to examine the up and down vibration of a train set. The test rig consists of three sub-hardware components: (i) a driving roller mechanism with a three-phase AC motor and an inverter, (ii) a bogie structure with first and second suspensions, and (iii) the vehicle body. The motor of the rig is capable of 3,600rpm, allowing the test to simulate a vehicle up to a maximum speed of 400Km/hr. Because bearings and joints are properly connected to the sub-structures, various motion analyses, such as a lateral, pitching, and yawing motion, are allowed. The slip motion between the rail and the wheel set is also monitored by several sensors mounted in the rig. After the construction of the hardware, an experiment is conducted to obtain the natural frequencies of the dynamic behavior of the specimen. First, the test rig is run and data are collected from six sets of accelerometers. Then, a numerical analysis of the model based on the ADAMS program is derived. Finally, the measurement data of the first three fundamental frequencies are compared to the analytical result and the validation of the test rig is conducted. The results show that the developed roller rig provides good accuracy in simulating the dynamic behavior of the vehicle motion. Although the roller rig designed in this paper is intended for academia, it can easily be implemented as part of a dynamic experiment of a bogie and a vehicle body for a high-speed train as part of the research efforts in this area.
A Study on Interior Noise Characteristics of High-speed Trains
Noh, Hee-Min ; Choi, Sunghoon ; Kim, Seog-Won ; Hong, Suk-Yoon ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 14~19
DOI : 10.7782/JKSR.2013.16.1.014
Because excessive interior noise when riding a high-speed train leads to annoyances, fatigue and stress for passengers, interior noise reduction methods should be considered. In particular, a high-speed train operated in various operation environments, and in South Korea, these include open fields and tunnels. Therefore, a specific study about changes in interior noise characteristics according to different environments is necessary. For this reason, the interior noise characteristics on a KTX train and on the KTX-Sancheon train were analyzed from noise measurements using microphones in this paper. Vibrations on the axles, bogies and floor were also measured, are these area are structural paths for interior noise. From this research, the interior noise characteristics according to the driving speed were deduced and the effects on interior noise by driving environments such as open fields and tunnels were investigated. Furthermore, the effect on interior noise by axles, bogies and floor vibrations were analyzed from a transfer function analysis.
A Method of Analysis to Predict Sound Transmission Loss of an Extruded Aluminum Panel for Use on Railway Vehicles
Kim, Kwanju ; Lee, Jun-Heon ; Kim, Dae-Yong ; Kim, Seock-Hyun ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 20~25
DOI : 10.7782/JKSR.2013.16.1.020
The frame elements of modern high speed trains are typically fabricated with extruded aluminum panels. However, the sound transmission loss (STL) of extruded aluminum panels is less satisfactory than flat panels with the same surface density. This study proposes a method for prediction of the sound transmission loss of extruded aluminum panels using finite element analysis. The panel is modeled by finite element analysis, and the STL is calculated using a measure of Sommerfeld radiation at the specimen surface, boundary conditions, and the internal loss factor of the material. In order to verify the validity of the predicted value, intensity transmission loss was measured on the aluminum specimen according to ASTM E2249-02. The proposed method of analysis will be utilized to predict the sound insulation performance of extruded aluminum panels for railway vehicles in the design stage, and to establish measures for their improvement.
Fault Diagnosis of a High-speed Railway Reduction Unit Using Analysis of Vibration Characteristics
Ji, Hae Young ; Lee, Kang Ho ; Kim, Jae Chul ; Lee, Dong Hyoung ; Moon, Kyoung Ho ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 26~31
DOI : 10.7782/JKSR.2013.16.1.026
The reduction unit is one of the most important components for railway vehicles because the torque of the motor must be transmitted to the wheels of the vehicle by the reduction unit. The faults in the reduction units of high-speed trains are caused by damage such as gear, fatigue. These have serious impacts on safety of the train during operation. To address this development of a system for monitoring, fault diagnosis of the reduction unit is needed to keep the vehicle running safely. Before that can be accomplished, it is most important to understand the vibration characteristics of the reduction unit in a normal state. Vibration diagnosis technology using characteristic-analysis of vibration waveform and frequency is known to be the most effective method for fault diagnosis. In this paper, we analyzed the vibration characteristics of the reduction units two Korean high-speed trains (KTX and KTX II), under normal conditions, by two test methods (driving gear test, full-vehicle test).
Safety Evaluation of the Dynamic Behavior of HEMU-430X using the Accelerometers of UIC 518 OR
Ryu, Sang-Hyun ; Kim, Sang-Soo ; Hong, June-Hee ; Song, Doo-Sang ; Guo, Yang-Yang ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 32~39
DOI : 10.7782/JKSR.2013.16.1.032
The next generation high-speed train(HEMU-430X) is Korea's first electric multiple unit type, high speed vehicle resulting from a national R&D project. Tests have been conducted on the Kyungbu High Speed Line running at speeds up to 354.64km/h, and analysis of the dynamic behavior of the train was carried out to evaluate its safety. In this study, a simplified method using an accelerometer(the method specified in UIC 518 OR) was chosen to analyze the safety of the train's dynamic behavior. The section chosen for analysis section was
with respect to the maximum speed point. In addition, we analyzed the trend of this dynamic behavior with increasing speed by comparing the analyzed values with those of UIC 518 OR. The dynamic behavior results met the limit values of UIC 518 OR and the study indicates that this trend is predicted to continue at speeds above 354km/h.
Evaluation on the Applicability of the Conventional Roadbed Stiffness for High Speed Concrete Track
Lee, Jin Wook ; Lee, Seong Hyeok ; SaGong, Myung ; Lyu, Tae Jin ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 40~46
DOI : 10.7782/JKSR.2013.16.1.040
Based on Korean railway design standards, the thicknesses of the reinforced roadbeds of conventional and high speed railways are different, and so too, for the size distribution of the ballast particles. Accordingly, considerable cost would be required to increase operating speeds of conventional lines, in particular related to changing from a ballasted track system to a ballastless one. In this study, applicability of a roadbed which supports conventional ballasted track, for use as a ballastless track for a high speed rail line was examined. A reinforced roadbed for a conventional railway is 20cm thick, and the type of material used for a conventional reinforced roadbed is M-40 (crushed gravel for road embankments). A dynamics test was conducted to evaluate the occurrence of the permanent settlement of the track substructure. These results suggest that, without changes to the track substructure, an operational speed of 400km/h is feasible with a ballastless track. This result; however, is from laboratory experiments. Further studies, such as numerical analyses or field validation, are required.
An Experimental Study on Shield TBM Tunnel Face Stability in Soft Ground
Kim, Yong-Man ; Lee, Sang-Duk ; Choo, Seok-Yeon ; Koh, Sung-Yil ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 47~51
DOI : 10.7782/JKSR.2013.16.1.047
In this study, we carried out an experimental shield TBM excavation model test using a down-scale device in soft clay, to understand tunnel-face stability properties in relation to changes in slurry pressure. We performed five tests according to tunnel depth (0.5D, 0.75D, 1.0D, 1.25D, 1.5D), and compared theoretical tunnel-face pressure with model test results. The range in theoretical tunnel-face slurry pressure (
), which is determined by earth pressure and water level, was very similar to the model test result. This result was due to the more isotropic condition of the soft clay ground, than of rocky ground.
Suggestions for Improvement of Connectivity between Railway Stations in Small and Medium-sized Cities Based on a Survey Focused on the Joongang Line
Choi, Chang-Ho ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 52~58
DOI : 10.7782/JKSR.2013.16.1.052
This study discusses how transportation to connect railway stations in Korea's small and medium-sized cities can be improved, based on analysis of a survey on the Joongang Line. The analysis considered current problems in connectivity between parts of the Korean transportation system and suggests how to encourage more passengers to shift from private cars to railways. It was found that railway users in small and medium-sized cities hope for better connection between different modes of public transportation, especially for urban buses. However, there is not enough connectivity currently available; therefore it is crucial to establish a system of such connections, mainly focusing on urban buses. Furthermore, in order to minimize transfer distances and connect various transfer modes, plans for improvements of facilities are needed and governmental support should be provided.
Access and Egress Patterns of Travel to a Regional Railway Station Based on Transit Smart Card Data (Case study: Seoul Station during Chuseok Holiday)
Eom, Jin Ki ; Lee, Jun ; Lee, Kwang-Seop ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 59~64
DOI : 10.7782/JKSR.2013.16.1.059
This study analyzed passenger access and egress travel patterns related to a Korean regional railway station (Seoul station), then developed a binomial logit model. This model referred to bus and metro mode of access and egress during a national holiday (Chuseok 2009); obtained from transit smart card data. The results showed that 99% of passengers getting access to, or egress from, the regional railway station did so using less than two transfers, and that most passengers were more likely to choose a metro. However, the passengers that made access or egress trips near Seoul Station were more likely to take a bus. From the results of the mode choice model, it was found that the impact of travel time was greater than that of travel cost, in the choices made for both access and egress. Interestingly, the impact of travel time is much greater in choosing the mode of egress.
Calculating and Improving Operational Decision-Making Indices for Public Railways by Inclusion of Non-economic Factors
Yang, Jungyu ; Ha, Ohkeun ; Kim, Ikhee ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 65~70
DOI : 10.7782/JKSR.2013.16.1.065
In many cases, operation of regional trunk lines is not profitable to railway operators. Nevertheless, railway operators are under pressure to manage regional trunk lines running under deficits, to better serve public interests. Given this situation, railway operators need to optimize assets by adjusting train schedules or changing the number of trains running. When railway operators judge the operation of a regional trunk line, the B/C ratio is generally used as a management index. This ratio is not considered part of strategic operational policy over the long term, and excessively influenced by the aspects of supply and demand over the short term. Accordingly, this study focused on indices that might be used to prevent worsening deficits and provide long term strategic operation policies, main indices to better measure economic situations, and auxiliary indices to supplement the main index. The main indices were measured in conventional ways to target experts and employees. This study presents quantitative standards, which are intended to be used to create itemized criteria through an Analytic Hierarchy Process, for better decision-making.
Effect of KTX Attendants' Emotional Labor on Emotional Exhaustion and Turnover Intention
Kim, Tae-Seon ; Hur, Chan-Young ; HwangBo, Jak ;
Journal of the Korean society for railway, volume 16, issue 1, 2013, Pages 71~77
DOI : 10.7782/JKSR.2013.16.1.071
This study analyzes how deep acting and surface acting, both classified as emotional labor, influence emotional exhaustion and turnover-intention for 263 KTX attendants. The followings are the summarized results of our analysis. First, the deep acting of KTX attendants does not affect emotional exhaustion, but surface acting was found to have a positive influence on emotional exhaustion. Second, the deep acting of KTX attendants had a positive impact on turnover-intention, but surface acting did not affect turnover-intention. Last, the emotional exhaustion of KTX attendants had a positive impact on turnover-intention. In conclusion, these results imply that it is important for employers to manage their employees' emotion in order to prevent turnover among KTX attendants.